Concentration of aqueous colloidal dispersions of polytetrafluoroethylene



toim nn 4 i atent 7 3,037,953 Patented June 5, 1962 dice 3,037,953CONCENTRATION OF AQUEOUS COLLOIDAL DIS- PERSIONS FPGLYTETRAFLUGROETHYLENE Barnard Mitchel Marks, Wilmington, Del., andGeorge Henry Whipple, Orange, Tex., assignors to E. l. du Pont deNemours and Company, Wilmington, Del., a corporation of Eelaware NoDrawing. Filed Apr. 26, 1961, Ser. No. 105,533 Claims. (Cl. 260-296)This invention relates to a process for concentrating dispersions ofpolytetrafiuoroethylene, and, more particularly, it relates to a processfor quickly concentrating aqueous, colloidal dispersions ofpolytetrafluoroethylene without the formation of coagulum.

This application is a continuation-in-part of our copending applicationSerial No. 772,416, filed November 7, 195 8, now abandoned, which, inturn, was a continuationin-part of our copending application Serial No.631,392, filed December 31, 1956, now abandoned, which, in turn, was acontinuation-in-part of our application Serial No. 356,584, filed May21, 1953, now abandoned, and Which, in turn, was a continuation-impartof our application Serial No. 348,116, filed April 10, 1953, nowabandoned.

Aqueous dispersions of polytetrafluoroethylene are commerciallyavailable at various concentrations, although the most common isapproximately 30% to 45% solids. Such dispersions can be made, forexample, according to the processes described in US. Patent 2,534,058issued to Malcolm M. Renfrew December 12, 1950, US. Patent 2,559,749issued to Anthony F. Benning July 10, 1951, and US. Patent 2,559,752issued to Kenneth L. Berry July 10, 1951, in which polyfluorinatedsalts, including the perfluorinated salts as well as the related saltswhich are highly, but not completely fluorinated, are employed as ionicdispersing agents. Dispersions with a concentration level of 30% to 45%solids are usefully employed in many applications; however, many of thesame applications, as well as other embodiments, find it advantageous toutilize dispersions of a higher concentration than 45%. For example, inthe field of coating or impregnating other materials by dipping,brushing, or spraying followed by evaporation of the continuous phase ofthe dispersion, it may be economical to use a highly concentrateddispersion and thereby increase the amount of solids applied to thesubstrate in one coating application. There are many materials which aresensitive to water and other liquids, such that it is desirable todecrease the time during which the sensitive material is in contact withthe liquid. It would therefore be advantageous to utilize a highlyconcentrated dispersion in such a case, if the sensitive material wereto be treated with a dispersion, and thereby minimize the time ofcontact. For example, if water-sensitive paper is to be treated with anaqueous dispersion of polytetrafiuoroethylene so as to coat the paper,it is advantageous to utilize a concentrated dispersion and thusminimize the time during which the paper is in contact with water.Moreover, it is more economical to use concentrated dispersions becauseof the decrease in operating time for a process utilizing such adispersion, as Well as requiring less space to store and ship suchdispersions.

Procedures for concentrating aqueous dispersions ofpolytetrafiuoroethylene may be found in US. Patent 2,478,229 issuedAugust 9, 1949, to K. L. Berry. This patent describes several methodswhereby the dispersing agent in the original dilute dispersion isrendered inactive so as to permit the dispersed polymer particles toflocculate or, in other words, to form larger size particles than in theoriginal dispersion. The flocculated particles, being heavier thanWater, settle into a concentrated non-fluid layer, and the supernatantliquid is then removed. It is then stated that the flocculated particlesmay be redispersed by peptizing the inactive dispersing agent. ThisBerry patent teaches three procedures to affect the concentration,namely 1) the addition of an acid to cause flocculation followed byneutralization of the acid to permit redispersion of the flocculatedparticles, (2) the addition of a water-soluble salt to a dispersioncontaining an ionic surface-active agent to cause the surface-activeagent to precipitate and, thereby, to permit the dispersed particles toflocculate and settle, followed by reducing the salt concentration (e.g.by volatilizing the dissolved salt) to permit the fiocculated particlesto redisperse, and (3) the heating of a dispersion containing anon-ionic surface-active agent to cause the surface-active agent toinsolubilize and, thereby, permitting the dispersed particles toflocculate and to settle, followed by cooling to resolubilize thesurface-active agent causing the flocculated particles to redisperse.While these procedures performed well in the concentration of relativelydilute (1%5% by weight of solids) dispersions ofpolytetrafluoroethylene, it has been found that modifications of theseprocedures are necessary to concentrate the polytetrafluoroethylenedispersions of today, which, in their dilute condition, contain 30%-45%of solids. Such concentrated disper sions were not available to Berry atthe time of 'his invention relating to methods of concentrating, andmore recent methods of polymerizing tetrafluoroethylene have made itpossible to obtain colloidal dispersions of about 30%-45% by weightsolids, which can, in turn, by the process of this invention be furtherconcentrated to 55 by Weight of solids. The dilute aqueous dispersionsof today are made by the processes of the Berry Patent US. 2,559,752 andcontain about 0.2%-0.4% of an ammonium polyfluorocarboxylate (based onthe weight of polymer solids) as a dispersing agent. It is thisdispersion which is employed as the starting material of the processdescribed and claimed herein.

If the concentration procedures of Berry US. 2,478,229 are applied tothis dilute aqueous dispersion (30%-45% solids and containing 0.2%0.4%ammonium polyfiuorocarboxylate) the dispersion does not concentrate astaught by Berry, and this is apparently due to a combination of suchfactors as (1) the presence of the ammonium polyfluorocarboxylate, whichis an ionic material, (2) the strong tendency for the colloidalparticles of polytetra fiuoroethylene to coagulate (i.e. to agglomerateirrreversibly, thereby unalterably destroying the colloidal nature ofthe dispersion), and (3) the greater concentration of the dilutedispersion causing the concentrating procedure to be a more delicateoperation. These factors are so important that the addition of aWater-soluble salt to a colloidal dispersion of polytetrafluoroethylene,whether that dispersion contains ammonium polyfiuorocarboxylate or not,causes the dispersed particles to coagulate. If the concentratingprocedures of the Berry Patent 2,478,229, which involve the addition ofan acid or the addition of 'a salt to a dispersion containing an ionicsurface-active agent, are employed, coagulation of the colloidalparticles occurs. Theoretically, it might be possible to add an exactamount of acid or the combination of ionic surface-active agent and asalt which would permit concentration with -a minimum of coagulation,but practically it has been found to be impossible to attain such a finebalance in a commercial operation. Furthermore, when such dispersionsare employed to produce electrical insulation, residues of the ionic oracid materials reduce the dielectric constant of the insulation to suchan extent that the quality of the insulation is too poor for commercialutility. The Berry procedure, involving the addition of a non-ionicsurface-active agent to the produces some concentration but, dependingupon the characteristics of the particular dispersion being concentratedand upon the manner in which the concentration is carried out, the Berryprocess may take as much as 100 times as long to reach the sameconcentration as the present process, while in some instances it appearsthat the ultimate concentration that can 'be reached by the Berryprocess is less than that which is desired, i.e. 55%- 75 by weight ofsolids. 7

It has also been observed that Whenthe concentrated dispersions ofpolytetrafluoroethylene are cast into films, some dispersions arecapable of producing relatively thick, void-treecontinuous films, whileothers contain voids and cracks throughout the film unless the film isconsiderably thinner. Unexplainably, the dispersions concentrated by theBerry process cannot be cast into films that are free of cracks and areasthick as is the case with the product of this invention.

It is an object of this invention to provide a novel method forconcentrating an aqueous dispersion of polytetrafluoroethylenecontaining a polyfluoro salt as a dis: persing agent. It is anotherobject of this invention to concentrate such an aqueous dispersion ofpolytetrafluoroethylene without the formation of any coagulum at anytime during the concentrating procedure. It is another object of thisinvention to concentrate such a dispersion in the shortest timepossible, which may be a matter of minutes or a few hours. It is anotherobject of this invention to provide a process for preparing aconcentrated dispersion of polytetrafiuoro'ethylene which can be castinto crack-free films. Other objects will be .apparent to those-skilledin the art of making polymeric dispersions.

The above objects may be accomplished by a process which consistsessentially of the steps of (l) forming a mixture by adding to anaqueous colloidal dispersion of particles ofpolytetrafiuoroethylenecontaining 30%5 by weight of polymer solids andcontaining 0.2%0.4%,

based on the weight of said solids, of an ammonium poly-.fluorocarhoxylate having 7-10 carbon atoms per molecule,

0.01% to 1.0% by weight of said dispersion of a member of the groupconsisting of sodium hydroxide, ammonium hydroxide, and ammoniumcarbonate, and 6%-l2% 'by weight of said solids of a non-ionicsurface-active agent selected from the group of compounds having theformula 110w CHzGHshOH and (2) heating said mixture to a temperature of50 80 C. until said nonionic, surface-active agent begins toinsolubilize as indicated by a cloudy appearance in said mixture, andsaid particles settle to form in said mixture a lower layer containingthe polymer solids and a substantially clear upper layer; (3) decantingsaid upper layer; (4) reducing the temperature of said mixture to aboutroom temperature; and (5) recovering said lower layer as an aqueouscolloidal dispersion of particles of polytetrafluoroethylene having aconcentration of 55%75% by Weight of solids and being free ofirreversibly coagulated polytetrafluoroethylene particles. In one of thepreferred embodiments of this process the above objects are accomplishedby starting with an aqueous colloidal polytetrafluoroethylene dispersioncontaining 30%-40% by weight l of solids and 0.2%0.4% by weight of thesaid solids of ammonium perfiuorocaprylate. To this dispersion there isadded 6-12% by weight of Triton" X-100 which is a polyethylene oxideether of octyl phenol having the general formula:

and sometimes named polyethylene glycol mono-paraoctylphenyl ether, and0.01%l.0% by Weight of the dispersion of sodium hydroxide, ammoniumhydroxide, or ammonium' carbonate. The remainder of the process stepsare thesame as those above, in that the dispersion active agent, whichis a polyethylene glycol ether having certain inverse solubilitycharacteristics, is important in causing the concentration to occurWithout the danger of coagulation. Thus, the original colloidal size of0.05 to 0.5 micron is retained, as the size of the polymer particles inthe concentrated product. In some unknown manner the polyethylene glycolether protects the particles of polytetrafiuoroethylene while theelectrolyte, in the form of sodium hydroxide, ammonium hydroxide orammonium carbonate, is neutralizing the electrostatic charges in thedispersion, presumably from the ammonium polyfluorocarboxylate used inthe polymerization step. As soon as these charges are neutralized, thepolymer particles move closer to each other and would coagulate were itnot for the presence of the polyethylene glycol ether. At temperaturesin the range of 5080 C. the ether becomes insoluble and seems to formtiny droplets giving the dispersion a cloudy appearance, and it isbelieved that these droplets form a nucleus around which the polymerparticles assemble during the sedimentation step. When the temperatureis lowered to room temperature the droplets disappear as the etherdissolves. The electrolyte neutralizes the charge, which is due to thepresence of the ammonium polyfluorocarboxylate, and thereby permits theconcentration step to proceed with much greater speed. The relativespeeds of concentration which are involved are that the use ofelectrolyte permits the concentration to occur up to 100 times fasterthan the same process without an electrolyte.

The following examples are provided to demonstrate the operation of thisprocess, and to. describe its features in a more detailed manner. Ineach example the starting material is a dilute dispersion containing asan ionic dispersing agent the ammonium salt of a polyfiuoroalkanoicacid, as described in US. Patent 2,559,752. Parts. and percentages areby weight unless otherwise specified.

Example 1 The starting material was an aqueous dispersion of colloidalpolytetrafiuoroethylene particles, the dispersion containing 48% solidscontent. To 100 ml. of the starting dispersion at C., there Was added 9%of Triton X100, based on the weight of the polymer, and the compositionWas mixed Well. Then lead acetate was added in various amounts indicatedbelow, and the mixture held at 80 C. to permit the concentrating actionto take place. Supernatant liquid was decanted and the following eifectswere obtained:

(a) 0.02 gram of lead acetate caused a concentration of 62% solids toform in less than an hour.

(b) 0.05 gram of lead acetate caused a concentration of 75% solids toform in less than an hour.

(0) 0.10 gram of lead acetate caused a concentration of 57% solids toform in less than an hour.

(d) 0.15 gram of lead acetate caused a concentration of 52% solids toform in less than an hour.

(e) 0.65 gram of lead acetate caused no concentration in two hours.

spa /395% Examples 2-9 in the following table there is a summary of aseries of runs in which a dilute dispersion of colloidalpolytetrafluoroethylene particles, having 0.2%-0.4% by the remaindercooled to give a colloidal dispersion of greater than 69% solids.

Example 13 weight of an ammonium polyfiuorocarboxylate in the dis- 5 Toan aqueous colloidal dispersion of polytetrapersion as a dispersingagent, is concentrated by treatfluoroethylene containing 31% solidsthere were added ment with a non-ionic surface-active agent and an elec-12% based on the weight of the polymer of a polytrolyte, followed by thesteps of heating, decanting and ethylene glycol alkyl ether (comprisedsubstantially cooling. In each of these examples the non-ionic, sur- 1of C H (OC H OH, an ethylene oxide adduct of face-active agent is TritonX-l00, and it is used in the O lauryl alcohol), and 0.35% by weight ofsaid dispersion amount of 9% by weight of the polymer solids. The ofammonium carbonate. The composition was mixed dispersion is then mixed,heated to the indicated temperwell at 52 C. and allowed to stand at thistemperature ature for the indicated time, decanted, and cooled to roomfor 2 hours, at the end of Which the supernatant hquid temperature torecover a dispersion concentrated to the was decanted and the remaindercooled to give a colloidal amount indicated. 15 dispersion of greaterthan 65% solids.

Percent by Percent of Tempera- Percent by Weight of Electrolyte tine toTime Weight of Example Polymer Electrolyte Based on which requiredPolymer Solidsin Added Weight of Dispersion for Concen- Sol dsinStarting Dispersion is Heated, tration Final Dispersion C. Dispersion 247 Oalgium chlo- 0.04 80 35 min 60 T1 0. 3 47 Barium chol- 0.06 8016min.... 63

6. 4 47 Ar nnionium 0.04 80 min 63 chloride. 5 50.7 Ammonium 0.04 80 12min 72 carbonate. 6 44 Ammonium 0.36 75 1.0 hr 68 hydroxide. 7 42 .do0.36 79 1.0hr 66 8 0.40 78 min-. 70 9 0.40 74 min 70 Example 10 Example14 35 To an aqueous, colloidal dispersion of polytetrafiuoroethylenecontaining 35% solids there were added 19.76 ml. of H 0 per 100 ml. ofdispersion, 9% based on the weight of the polymer of a polyethyleneglycol alkyl ether (comprised substantially of C H (OC H OH, an 4ethylene oxide adduct of oleyl alcohol), and 0.18% by weight of thedispersion of concentrated ammonium hydroxide. The composition was mixedwell at 75 C. and allowed to stand at this temperature for 1 /2 hours,at the end of which time the supernatant liquid was decanted andtheremainder cooled to give a colloidal dispersion of 67% solids.

Example 11 To an aqueous, colloidal dispersion ofpolytetrafluoroethylene containing 35% solids there were added 19.76 ml.of H O/ 100 ml. dispersion, 9% based on the weight of the polymer of apolyethylene glycol alkyl ether (the ethylene oxide adduct of acommercial mixture of aliphatic alcohols, about cetyl alcohol and /3stearyl alcohol, the adduct containing about 10 moles of ethylene oxideper mole of alcohol), and 0.36% by weight of the dispersion ofconcentrated ammonium hydroxide. The water was added to bring theresulting solids content to 30%, but is not necessary in the process.The composition was mixed well at 66 C., and was allowed to stand atthis temperature for 1 /3 hours, at the end of which time thesupernatant liquid was decanted and the remainder cooled to give acolloidal dispersion of greater than 68% solids.

Example 12 To an aqueous, colloidal dispersion ofpolytetrafluoroethylene containing 39% solids there were added 32.64 ml.H O per 100 ml. of dispersion, 9% based on the weight of the polymer ofa polyethylene glycol alkyl ether (comprised substantially of C H (OC HOH, an ethylene oxide adduct of lauryl alcohol, and 0.35% by weight ofpolymer solids of concentrated ammonium hydroxide. The composition wasmixed well at 65 C. and allowed to stand at this temperature for 35minutes, at the end of which the supernatant liquid was decanted and Toan aqueous colloidal dispersion of polytetrafluoroethylene containing35% solids there were added 19.76 ml. of H 0 per ml. of the dispersion,9% based on the weight of the polymer of a mixture of equal parts byweight of two polyethylene glycol alkyl ethers 0.72% by weight of saiddispersion of concentrated am monium hydroxide. The composition wasmixed well at 63 C. and allowed to stand at this temperature for 1 /2hours, at the end of which time the supernatant liquid was decanted andthe remainder cooled to give a colloidal dispersion of 64% solids.

In all of the examples given above the concentrated product dispersionis free-flowing, With the polymer completely dispersed, in a colloidalparticle size of 0.05 to 0.5 micron, and containing no coagulatcdmaterial. The viscosity of the product dispersion is from about 10 toabout 20 cps.

The electrolytes used in the process of this invention are important inthat their use has permitted a concentrating action to take place in ahalf to a hundredth of the time required to accomplish the same resultby methods known heretofore. Furthermore, the use of an elecr trolyteeliminates the necessity 'of maintaining a delicate control over thetime-temperature relationships of this process.

The electrolytes known to be operable in the process of concentratingpolytetrafiuoroethylene dispersions include any base or any salt whichionizes in the dispersion. There are many reasons why it is desirable tochoose one compound over another for use as the electrolyte of thisprocess. In some instances it is important not to employ a non-volatileelectrolyte. When a polytetrafluoroethylene dispersion containing anon-volatile electrolyte is used in the preparation of a shaped articlewhich must be sintered in order to fuse the polymer particles, thenon-volatile material remains in the coating as an impurity. Thepresence of these impurities can lead to undesirable results, if thepolymer is to be used as a corrosion-resistant material or as electricalinsulation. For such purposes it is desirable for the process ofelectrolyte to the total weight of the dispersion.

' tration will be effected quicker.

of this invention touse water-soluble ammonium electrolytes. For otherreasons, it has been found to be desirable in one embodiment of thisinvention to employ sodium hydroxide as the electrolyte. Accordingly,this invention includes the use of ammonium hydroxide, ammoniuincarbonate, and sodium hydroxide as the electroilytes in this process. a

The amount of electrolyte used in this invention depends on variousfactors of the reaction, a1though it generally is desirable to maintainthe electrolyte concencases tration as small "as possible, and yetwithin the operable range. It has been found convenient to relate theamount In the case of sodium hydroxide and of ammonium carbonate, 0.01%to 0.5% by weight of the dispersion has been found to be preferred inthe concentration of a dispersion from about 30% solids to about 65%solids or more. In the case of concentrated ammonium hydroxide, 0.05% to0.75% by Weight of the dispersion constitutes the preferred'amount. Itis apparent that more dilute solutions of ammonium hydroxide might beused, in which event the amounts to be used would vary so as to provideamounts equivalent to those given above for the concentrated solution.As a general statement, it may be said that the electrolyte should bepresent in the amount of 0.01% to 1.0% by weight of the dispersion.

mulas may not be whole numbers, and this is intended to cover the factthat any commercial compound might prove to be a mixture of compoundswhich diiier only by the number of ethylene oxide units.

In order to understand the interaction of variables in this process,some explanation may be in order so that one may successfully employthis process. The amount of ammonium polyfluorocarboxylate, the amountand kind of non-ionic surface-active agent, the amount and kindof'electrolyte, and the temperature of the concentration process are allimportant variables which must be balancedJ For example, as one uses anon-ionic, surfaceactive agent with an increasingly larger number ofethylene oxide units, it may be necessary to increase the temperature ofthe cencentrvation, to increase the amount of electrolyte, or toincrease the amount of the surface-active agent in order to make theprocess operate in the most satisfactory manner. As another example, ifone increases the amount of the surface-active agent used in theProcess, it may be necessary to decrease the amount of electrolyte or todecrease the temperature in order for the process to operatesatisfactorily. Other interactions may be apparent to those skilled inthe art.

The concentrated dispersions of this invention are useful for thecasting of films, impregnating certain papers,

' textiles, glass-fiber materials, and felted materials, coat- Thetemperature at which the concentrating action takes 7 place should befrom about 50 C. to about 80 C. The preferred range of temperature isfrom about 70 C.

to about "80 C. Concentration may take place at lower temperatures, butin order to achieve the most speed and,

thereby, to reduce costs, the temperatures should be those given above.The rate at which the original dispersion is heated to its concentratingtemperature is unimportant in this process. Certain embodiments of thisinvention will permit concentrations of a desired degree 1. A processfor concentrating aqueous, colloidal dispersions ofpolytetrafluoroethylene which consists essentially of the steps of (1)forming a mixture by adding to an aqueous colloidal dispersion ofparticles of polyto occur within 15 minutes, while other embodiments mayrequire one or two hours. The rate of concentration is slow in the firstminute or two of the heating period, increases to a rapid rate, and thentapers'ofi to slower rates. It has also been found that, if the surfaceof the dispersion is large, evaporation and concen- For manyapplications of this invention, a heating period of 15 minutes to anhour is sufiicient to increase the concentration of apolytetrafluoroethylene.dispersion from an initial value of about 30% toa final concentration of 65% solids or more. 7

The non-ionic surface-active agent employed in this process is any of agroup of polyethylene glycol ethers having the formula; Y

Where R is a monovalent hydrocarbon radical of 8-10 carbon atoms, r is apositive number having a value of .1-2 more than the number of carbonatoms in'R, n is a positive integer from 12-18, and m is a positivenumber having, a value from tetrafluoroethylene containing 30%-50% byweight of polymer solids and containing 0.2%0.4%, based on the weight ofsaid solids, of an ammonium polyfluorocarboxylate having 7-10 carbonatoms per molecule, 0.01% to 1.0% byweight of said dispersion of amember of the group consisting of sodium hydroxide, ammonium hydroxide,and ammonium carbonate, and 6%-12% by weight of said solids-of anon-ionic surface-active agent selected from the group consisting ofcompounds having the formula R-QwonionnmH and compounds having theformula n zni 1 z a) m wherein R is a monovalent hydrocarbon radical of8-10 carbon atoms, 1' is a positive number having a value equal to 1 to2 more than the number of carbon atoms in R, n is a positive integer offrom 12-18, and m is a number having the value of from (2) heating saidmixture to a temperature of 50-80 C.

' until said non-ionic, surface-active agent begins to instantiallyclear upper layer; (3) decanting said upper layer; (4) reducing thetemperature of said mixture. to

about room temperature; and (5) recovering said lower layer as anaqueous colloidal dispersion of particles of polytetrafiuoroethylenehaving a concentration of 55%- by weight of solids and being free ofirreversibly coagulated' polytetrafiuoroethylene particles.

2. The process of claim 1 in which said non-ionic surface-active agenthas the formula rtsmar myn-- o CHCHa) M on 3,087,958 9 10 3. The processof claim 1 in which said non-ionic References Cited in the file of thispatent surface-active agecnt IhIas 2121301321121 OH UNITED STATESPATENTS 12 2 Berry Aug. 9, 1949 4. The process of claim 1 m which saidnon-ionic 5 Berry July 10 1951 surface-active agent has the formula C H(OCH CH OH OTHER REFERENCES 5. The process of claim 1 in whi h theammonium Industrial and Engineering Chemistry, volume 44, hydroxide isemployed in the amount of 0.05 %0.75% 10 N0. 8, pages 1800-1805, August1952. by weight of said dispersion.

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No.3,037,953 June 5, 1962 Barnard Mitchel Marks et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 3, line 52 the formula should appear as shown below instead of asin the patent:

c n l (0CH CH OH column 8, lines 73 to 75, the formula should appear asshown below instead of as in the patent:

(tertiary-octyl (0CH CH OH (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents

1. A PROCESS FOR CONCENTRATING AQUEOUS, COLLOIDAL DISPERSIONS OFPOLYTETRAFLUOROETHYLENE WHICH COSISTS ESSENTIALLY OF THE STEPS OF (1)FORMING A MIXTURE BY ADDING TO AN AQUEOUS COLLOIDAL DISPERSION OFPARTICULES OF POLYTETRAFLUOROETHYLENE CONTAINING 30%-50% BY WEIGHT OFPOLYMER SOLIDS AND CONTAINING 0.2%-0.4%, BASED ON THE WEIGHT OF SAIDSOLIDS, OF AMMONIUM POLYFLUOROCARBOXYLATE HAVING 7-10 CARBON ATOMS PERMOLECULE, 0.01% TO 1.0% BY WEIGHT OF SAID DISPERSION OF A MEMBER OF THEGROUPS CONSISTINGOF SODIUM HYDROXIDE, AMMONIUM HYDRXIDE, AND AMMONIUMCARBONATE, AND 6%-12% BY WEIGHT OF SAID SOLIDS OF A NON-IONICSURFACE-ACTIVE AGENT SELECTED FROM THE GROUP CONSISTING OF COMPOUNDSHAVING THE FORMULA